/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.metadata.tagSchemaRegion.tagIndex.deletion;

import org.apache.iotdb.db.metadata.tagSchemaRegion.tagIndex.Request.DeletionRequest;
import org.apache.iotdb.db.metadata.tagSchemaRegion.tagIndex.memtable.MemChunkGroup;
import org.apache.iotdb.db.metadata.tagSchemaRegion.tagIndex.memtable.MemTable;
import org.apache.iotdb.lsm.annotation.DeletionProcessor;
import org.apache.iotdb.lsm.context.requestcontext.DeleteRequestContext;
import org.apache.iotdb.lsm.levelProcess.DeleteLevelProcessor;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

/**
 * deletion for MemTable
 */
@DeletionProcessor(level = 1)
public class MemTableDeletion
        extends DeleteLevelProcessor<MemTable, MemChunkGroup, DeletionRequest> {

    /**
     * get all MemChunkGroups that need to be processed in the current MemTable
     *
     * @param memNode memory node
     * @param context request context
     * @return A list of saved MemChunkGroups
     */
    @Override
    public List<MemChunkGroup> getChildren(
            MemTable memNode, DeletionRequest deletionRequest, DeleteRequestContext context) {
        if (memNode.isImmutable()) return new ArrayList<>();
        List<MemChunkGroup> memChunkGroups = new ArrayList<>();
        String tagKey = deletionRequest.getKey(context);
        MemChunkGroup child = memNode.get(tagKey);
        if (child != null) memChunkGroups.add(child);
        return memChunkGroups;
    }

    /**
     * the delete method corresponding to the MemTable node
     *
     * @param memNode memory node
     * @param context deletion request context
     */
    @Override
    public void delete(
            MemTable memNode, DeletionRequest deletionRequest, DeleteRequestContext context) {
        if (memNode.isImmutable()) {
            Set<Integer> deletionList = memNode.getDeletionList();
            if (!deletionList.contains(deletionRequest.getValue())) {
                deletionList.add(deletionRequest.getValue());
            }
            return;
        }
        String tagKey = deletionRequest.getKey(context);
        MemChunkGroup child = memNode.get(tagKey);
        if (child == null || child.isEmpty()) {
            memNode.remove(tagKey);
        }
    }
}
